This book constitutes the refereed proceedings of the Fourth International Conference on High Performance Embedded Architectures and Compilers, HiPEAC 2009, held in Paphos, Cyprus, in January 2009.

Invited Program.- Keynote: Challenges on the Road to Exascale Computing.- Keynote: Compilers in the Manycore Era.- I Dynamic Translation and Optimisation.- Steal-on-Abort: Improving Transactional Memory Performance through Dynamic Transaction Reordering.- Predictive Runtime Code Scheduling for Heterogeneous Architectures.- Collective Optimization.- High Speed CPU Simulation Using LTU Dynamic Binary Translation.- II Low Level Scheduling.- Integrated Modulo Scheduling for Clustered VLIW Architectures.- Software Pipelining in Nested Loops with Prolog-Epilog Merging.- A Flexible Code Compression Scheme Using Partitioned Look-Up Tables.- III Parallelism and Resource Control.- MLP-Aware Runahead Threads in a Simultaneous Multithreading Processor.- IPC Control for Multiple Real-Time Threads on an In-Order SMT Processor.- A Hardware Task Scheduler for Embedded Video Processing.- Finding Stress Patterns in Microprocessor Workloads.- IV Communication.- Deriving Efficient Data Movement from Decoupled Access/Execute Specifications.- MPSoC Design Using Application-Specific Architecturally Visible Communication.- Communication Based Proactive Link Power Management.- V Mapping for CMPs.- Mapping and Synchronizing Streaming Applications on Cell Processors.- Adapting Application Mapping to Systematic Within-Die Process Variations on Chip Multiprocessors.- Accomodating Diversity in CMPs with Heterogeneous Frequencies.- A Framework for Task Scheduling and Memory Partitioning for Multi-Processor System-on-Chip.- VI Power.- Hybrid Super/Subthreshold Design of a Low Power Scalable-Throughput FFT Architecture.- Predictive Thermal Management for Chip Multiprocessors Using Co-designed Virtual Machines.- HeDGE: Hybrid Dataflow Graph Execution in the Issue Logic.- Compiler Controlled Speculationfor Power Aware ILP Extraction in Dataflow Architectures.- VII Cache Issues.- Revisiting Cache Block Superloading.- ACM: An Efficient Approach for Managing Shared Caches in Chip Multiprocessors.- In-Network Caching for Chip Multiprocessors.- VIII Parallel Embedded Applications.- Parallel LDPC Decoding on the Cell/B.E. Processor.- Parallel H.264 Decoding on an Embedded Multicore Processor.